U.S. patent number 5,621,515 [Application Number 08/366,181] was granted by the patent office on 1997-04-15 for identification system using regions of predetermined properties interspersed among regions of other properties.
This patent grant is currently assigned to NHK Spring Co., Ltd.. Invention is credited to Hidekazu Hoshino, Kazuhiro Kitada.
United States Patent |
5,621,515 |
Hoshino , et al. |
April 15, 1997 |
Identification system using regions of predetermined properties
interspersed among regions of other properties
Abstract
In an article identification system comprising a plurality of
identification regions affixed on an article, a light emitting
device for impinging an illuminating light beam onto at least some
of the identification regions, a light receiving device for
detecting light diffracted by the identification regions, and a
determination unit for determining the authenticity of the article
according to a pattern of diffracted light detected by the light
receiving device, the identification regions consist of a
combination of effective and ineffective identification regions
which are hardly distinguishable by naked eyes. Thus, the potential
forger is not able to know which regions are indeed effective
without having any access to a genuine optical reader/writer, and
has to duplicate all of the identification regions at a substantial
cost and requiring a substantial amount of effort. On the other
hand, the genuine optical reader/writer can simply disregard all of
the ineffective identification regions, and the cost of the article
identification system can be substantially reduced. Therefore, for
given effort and cost, the effectiveness of the article
identification system to discourage illicitly duplication can be
increased.
Inventors: |
Hoshino; Hidekazu
(Kanagawa-ken, JP), Kitada; Kazuhiro (Kanagawa-ken,
JP) |
Assignee: |
NHK Spring Co., Ltd.
(Kanagawa-ken, JP)
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Family
ID: |
12121689 |
Appl.
No.: |
08/366,181 |
Filed: |
December 29, 1994 |
Foreign Application Priority Data
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Jan 25, 1994 [JP] |
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6-023843 |
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Current U.S.
Class: |
356/71; 235/457;
235/494; 283/86; 359/2 |
Current CPC
Class: |
G03H
1/041 (20130101); G06K 19/18 (20130101) |
Current International
Class: |
G03H
1/04 (20060101); G06K 19/18 (20060101); G06K
009/74 (); G06K 007/10 (); G03H 001/00 (); B42D
015/00 () |
Field of
Search: |
;356/71 ;283/86 ;359/2
;235/457-494 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0533448A2 |
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Mar 1993 |
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EP |
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92/004692 |
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Mar 1992 |
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WO |
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Primary Examiner: Gonzalez; Frank
Assistant Examiner: Eisenberg; Jason D.
Attorney, Agent or Firm: Skjerven, Morrill, MacPherson,
Franklin & Friel MacPherson; Alan H. Suryadevara; Omkar K.
Claims
What we claim is:
1. An article identification system comprising a plurality of
identification regions affixed on an article, a light emitting
device for impinging an illuminating light beam onto at least some
of said identification regions, a light receiving device for
detecting light diffracted by said identification regions, and a
determination unit for determining authenticity of said article
according to a pattern of diffracted light detected by said light
receiving device,
wherein said light receiving device comprises a plurality of
sectors around the light emitting device;
wherein said identification regions further comprise a combination
of effective and ineffective regions which are substantially
indistinguishable from each other by naked eyes;
wherein at least two of said effective identification regions have
diffractive properties different from each other, and said
ineffective identification regions have at least one diffractive
property different from those of said effective identification
regions;
wherein said pattern of diffracted light is formed by encoded data
wherein said encoded data is in said effective identification
region; and
wherein the authenticity is determined by said determination unit
based on where said diffracted light leaving said encoded data
impinges on predetermined sectors in said plurality of sectors of
said light receiving element.
2. An article identification system according to claim 1, wherein
said effective identification regions are arranged along a track
defined on said article for scanning by said light emitting and
receiving devices.
3. An article identification system according to claim 2, wherein
said light emitting and receiving devices and said determination
unit detect the length of each of said effective identification
regions.
4. An article identification system according to claim 1, wherein
the light receiving device comprises a plurality of sectors
concentrically surrounding the light emitting device.
5. An article identification system according to claim 1, wherein
said article has a front surface and further wherein said effective
identification regions are distributed substantially over the front
surface.
Description
TECHNICAL FIELD
The present invention relates to an article identification system
for identifying the authenticity of an article.
BACKGROUND OF THE INVENTION
Conventionally, identification seals carrying hologram and other
marks that cannot be readily forged have been affixed to articles
such as credit cards, monetary papers, tickets and commercial goods
to discourage any attempts to illicitly duplicate them.
These identification seals are normally intended to be visually
identified, and are therefore placed in highly visible places.
These identification seals are thus so visible that it is
relatively easy for a potential forger to analyze the structure of
the identification seals. Furthermore, forgery of such
identification seals is relatively easy because it suffices if the
forged identification seal can successfully deceive the eye of the
user.
It was also proposed to use an optical reader to identify an
identification seal. Examples of such article identification
systems are found in the description of a number of commonly
assigned United States patents, and for more details of this
technical field reference should be made, for instance, to U.S.
Pat. Nos. 5,300,764 issued Apr. 5, 1994, 5,291,006 issued Mar. 1,
1994, and 5,200,794 issued Apr. 6, 1993. Because the identification
process is carried out by a machine, the accuracy of identification
is improved as compared to the naked eye, and forgery can be
prevented even more effectively. However, it still is possible for
a potential forger to locate the position of the identification
region, and to analyze it with a certain amount of effort.
BRIEF SUMMARY OF THE INVENTION
In view of such problems of the prior art, a primary object of the
present invention is to provide an article identification system
which is highly effective in discouraging any attempts to illicitly
duplicate the identification region.
A second object of the present invention is to provide an article
identification system which can maximize the effectiveness of the
identification system at a minimum cost.
A third object of the present invention is to provide an article
identification system which can be implemented in an existing
article identification system with a minimum amount of
modification.
According to the present invention, these and other objects can be
accomplished by providing an article identification system
comprising a plurality of identification regions affixed on an
article, a light emitting device for impinging an illuminating
light beam onto at least some of the identification regions, a
light receiving device for detecting light diffracted by the
identification regions, and a determination unit for determining
the authenticity of the article according to a pattern of
diffracted light detected by the light receiving device, wherein
the identification regions consist of a combination of effective
and ineffective identification regions which are hardly
distinguishable by naked eyes.
Thus, the potential forger is not able to know which regions are
indeed effective without having any access to a genuine optical
reader/writer, and has to duplicate all of the identification
regions at a substantial cost and requiring a substantial amount of
effort. On the other hand, the genuine optical reader/writer can
simply disregard all of the ineffective identification regions, and
the cost of the article identification system can be substantially
reduced. Therefore, for given effort and cost, the effectiveness of
the article identification system to discourage illicit duplication
can be increased.
According to the preferred embodiments of the present invention,
the effective identification regions have a prescribed diffractive
property, and the ineffective identification regions have one or a
plurality of diffractive properties different from that of the
effective identification regions. The diffractive properties may be
readily detected by an optical reader, but are not easily
distinguishable by naked eyes. Obviously, the effective
identification regions may consist of a plurality of regions having
a combination of different identification regions. In this case, it
is possible to encode data in the identification regions.
If the effective identification regions are arranged along a track
defined on the article adapted to be scanned by the light emitting
and receiving devices, the optical reader can read the effective
identification regions with a simple structure and in a short
time.
By detecting the arrangement or the distribution of the effective
identification region, and detecting the length of each of the
effective identification regions, it is possible to encode useful
data in the identification regions, and to even more effectively
discourage any attempts to illicitly duplicate the identification
regions.
BRIEF DESCRIPTION OF THE DRAWINGS
Now the present invention is described in the following with
reference to the appended drawings, in which:
FIG. 1 is a perspective view of an essential part of a first
embodiment of the present invention applied to a system for
identifying the authenticity of a magnetic card;
FIG. 2 is a sectional side view of the light emitting device and
the light receiving device;
FIG. 3 is a plan view of the light emitting device and the light
receiving device;
FIG. 4 is an enlarged plan view of the identification regions
including true identification regions and fake identification
regions;
FIG. 5 is a view similar to FIG. 4 showing a second embodiment of
the present invention; and
FIG. 6a illustrates an output signal from the light receiving
device of FIG. 3.
FIGS. 6b-1 to 6b-4 illustrate signals from the respective sectors
(8a, 8e), (8b, 8f), (8c, 8g), and (8d, 8h).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 through 4 show a first embodiment of the present invention
applied to a magnetic card. As best illustrated in FIG. 1, this
magnetic card 1 carries a magnetic stripe 2 extending along a long
side of the card 1 on a front surface 1a thereof. The surface 1a is
also provided with a mark, which may be either a seal attached to
the card surface or printed directly on the card surface, serving
as an identification area 3. As described in more detail
hereinafter, the identification area 3 includes true identification
regions 3a and fake identification regions 3b.
A card reader/writer is provided with a magnetic head 4 which
opposes the magnetic stripe 2 as the magnetic card 1 is conveyed
through the card reader/writer by card conveying means not shown in
the drawings. The card reader/writer is additionally provided with
a light emitting/receiving unit 5 so as to be opposite the true
identification regions 3a as the magnetic card 1 is conveyed
through the card reader/writer. The light emitting/receiving unit 5
comprises a light emitting device 6 which projects an illuminating
light beam having the wavelength of 780 nm onto the true
identification regions 3a, and an annular light receiving device 8
concentrically surrounding the light emitting device 6 (refer to
FIGS. 2 and 3). The light emitting device 6 is so positioned as to
be opposite the true identification regions 3a when the card 1 is
placed at prescribed locations in the card reader/writer. The light
receiving device 8 consists of a multi-segment photodiode which is
divided into eight identical sectors 8a to 8h (FIG. 3) each capable
of individually detecting light, and is connected to a
determination unit 9 (FIG. 1) which consists of a CPU, memory, and
interface circuits, and is adapted to analyze the output from the
light receiving device 8 to determine the authenticity of the
magnetic card 1.
As best illustrated in FIG. 4, the identification region 3 is
provided in a part of the front surface of the magnetic card 1 not
interfering with the magnetic stripe 2, and the four patches 11,
12, 13 and 14 surrounded by the imaginary lines are defined as the
true identification regions 3a consisting of holograms and
demonstrating a certain diffractive property that can be detected
by the light emitting/receiving unit 5. The diffractive property of
the hologram O of the true identification regions 3a is such that
when the hologram is precisely opposite the light
emitting/receiving unit 5 the resulting diffracted light impinges
upon a prescribed pair or pairs of sectors 8a to 8h diagonally
opposing each other. Thus, which pair or pairs of the sectors 8a to
8h will detect the diffracted light depends on the specific:
diffractive property of the hologram O. The remaining holograms P,
Q and R of the fake identification regions 3b have different
diffractive properties from that of the hologram O.
When actually identifying the authenticity of the card 1, the card
1 is conveyed to positions at which the light emitting device 6 of
the light emitting/receiving unit 5 opposes the true identification
regions 3a. Then, an illuminating light having the wavelength of
780 nm is emitted from the light emitting device 6 and impinged
upon each of the true identification regions 3a. The light
diffracted by each of the true identification regions 3a impinges
upon a prescribed pair of the eight sectors 8a to 8h of the light
receiving device 8, and the authenticity of the card 1 can be
verified by the distribution of the intensities of the light
received by the eight sectors 8a to 8h. By rotating the direction
of diffraction of each of the true identification regions 3a, it is
possible to obtain four possible light emitting patterns in terms
of the intensities of light received by the eight sectors in the
case where the diffracted light impinges upon a symmetric pair of
the eight sectors; (1) sectors 8a and 8e, (2) sectors 8b and 8f,
(3) sectors 8c and 8g, and (4) sectors 8d and 8h. Therefore, by
determining the rotational angle of the hologram O, it is possible
to identify the authenticity of the card 1 according to the
presence of a hologram and the direction of diffraction.
Therefore, when a potential forger obtains an authentic magnetic
card 1 with the intention of illicitly duplicating the
identification area 3, he has to duplicate not only the true
identification regions 3a but also the fake identification region
3b as he has no way of knowing which of the regions are indeed
essential without having any access to a genuine card
reader/writer. Even if he gains access to a genuine card
reader/writer, as it is difficult enough to analyze the diffractive
property of the hologram, it would be extremely difficult for him
to successfully duplicate it.
The identification area was provided only in a part of the front
surface 1a of the magnetic card 1 in the above described
embodiment, but the identification regions may be distributed
substantially over the entire front surface 1a of the magnetic card
1. In this case, the true identification regions 3a can be hidden
in hardly noticeable parts of the card surface, and the difficulty
in finding the true identification regions 3a can be made even more
increased.
FIGS. 5 and 6a, 6b-1, 6b-2, 6b-3 and 6b-4 show a second embodiment
of the present invention which is also applied to a magnetic data
storage card, and the parts corresponding to those of the previous
embodiment are denoted with like numerals.
In this embodiment, eight letters A, B, C, D, E, F, G and H are
printed, attached or otherwise affixed on the front surface 1a of
the card 1, and some parts of the letter regions (shaded regions in
FIG. 2) consist of a hologram O having a prescribed identifiable
diffractive property while the remaining parts of the letter
regions consist of holograms P, Q and R having diffractive
properties different from that of the hologram O. In this
embodiment, the true identification regions 13a consist of patches
arranged along a track defined along a long side of the card 1 so
that the light emitting/receiving unit 5 can scan the true
identification regions 13a as the card 1 is conveyed through the
card reader/writer. The card reader/writer may simply detect the
presence of the true identification regions 13a. More preferably,
the card reader/writer detects the length of each of the true
identification regions 13a, and the distribution of the true
identification regions 13 so that the card 1 is identified to be
authentic only when the true identification regions 13a are
arranged in a prescribed pattern and have a prescribed combination
of lengths. The remaining parts of the letter regions consist of
fake identification regions 13b which are intended to camouflage or
conceal the true identification regions 13a from the eyes of
potential forgers.
In this embodiment also, depending on the direction of diffraction
of each of the identification regions 13a and 13b, there are four
possible patterns of light received by the different sectors 8a to
8h of the light receiving device 8. Thus, the authenticity of the
card 1 can be identified according to the distribution, the lengths
and the directions of diffraction of the identification regions 13.
An example of the pattern of the signals obtained by the different
sectors 8a to 8h of the light receiving device 8 is given in FIGS.
6a, 6b-1, 6b-2, 6b-3 and 6b-4.
Therefore, even when a person contemplating forgery has obtained an
authentic card 1, it is extremely difficult for him to distinguish
the true identification regions 13a from the fake identification
regions 13b if he has no access to a genuine card reader/writer.
Even if he succeeded in distinguishing the different diffractive
properties of the identification area 13, he still would not be
able to determine which of the identification regions are indeed
true identification regions.
Thus, unless the entire hologram area is reproduced, it is
virtually impossible to successfully duplicate the identification
regions. However, it is extremely expensive and requires a high
level of technology to reproduce holograms in a complex
arrangement, and it is not practical to make any attempt to
illicitly duplicate the card 1. Also, by changing the positions of
the true identification regions 13a from time to time, attempts to
forge the card will be even more effectively prevented.
The present invention is not limited to the above described
embodiments, and various other embodiments are possible. For
instance, in the above described embodiment, the diffractive
properties of the holograms were such that the diffracted light
impinged upon a pair of symmetrically placed sectors of the light
receiving device 8 in each case. However, the diffractive property
of the holograms can be designed so that the diffracted light
impinges upon only one of the sectors or upon three or more of the
sectors. By thus diversifying the possible patterns of diffracted
light, it is possible to store a large amount of useful information
in the identification regions.
In the above described embodiments, the identification regions were
affixed on a card, but the present invention can be applied to
other articles such as monetary papers such as checks, bonds,
promissory notes and coupons, commercial goods in general, and
packages for commercial goods. The term hologram as used in this
description should be interpreted in its broadest sense, and
includes various forms of diffraction grating.
* * * * *